Kendra decides to go door-to-door and survey people who live near the pet shop she owns. On Tuesday, Kendra steps out during her lunch break and finds that many people aren't home. Of the people who are home, Kendra discovers that most of them are elderly or stay-at-home parents. Discovering that many people are not available to participate in her survey is an example of bias. a.) nonresponse b.) response c.) unintentional d.) deliberate